atherosclerosis
Meaning of atherosclerosis: The sudden events, heart attack and most strokes, come less from slow narrowing than from a plaque tearing open and triggering a clot.
Definition of atherosclerosis
Atherosclerosis is the buildup of fatty deposits called plaque inside the walls of arteries. Plaque is a mixture of cholesterol, other fats, inflammatory cells, calcium and fibrous tissue. As it enlarges it narrows the channel blood flows through and stiffens the wall, cutting the supply to whatever the artery feeds. It builds silently over decades.
How does plaque form?
It begins in the wall of the artery, not on its inner surface. The smooth lining is irritated by long standing high blood pressure, tobacco smoke, high blood sugar or a high level of cholesterol carried on low density particles. Those particles slip into the wall and are chemically altered there. White blood cells follow, swallow the fat and become bloated foam cells, and a soft fatty core builds up beneath a cap of fibrous tissue. Calcium is deposited later, which is what makes established plaque visible on some scans. Early on the artery bulges outward to accommodate the deposit, so the channel stays open and nothing is felt, which is one reason the process runs for years unnoticed.
Why does rupture matter more than size?
A plaque with a thick fibrous cap can narrow an artery considerably and still behave predictably, producing chest tightness or leg pain that comes on with exertion and eases with rest. A plaque with a thin cap is a different problem. If the cap tears, blood meets the fatty core, platelets pile onto it and a blood clot can seal off the artery within minutes. That mechanism, rather than gradual narrowing, causes most heart attacks and many strokes, and it explains why an event can strike someone whose arteries were never severely narrowed.
How does it relate to arteriosclerosis?
| Term | What it describes |
|---|---|
| Arteriosclerosis | Any hardening or stiffening of arteries, used as the umbrella term |
| Atherosclerosis | The plaque forming type, and the one behind coronary heart disease |
| Arteriolosclerosis | Thickening of the smallest arteries, seen with long standing high blood pressure and diabetes |
Because atherosclerosis affects arteries throughout the body, the same disease shows up as chest pain from the heart arteries, stroke from those feeding the brain, and cramping calf pain on walking from those supplying the legs.
Used in a sentence
Imaging revealed atherosclerosis affecting the coronary arteries.
Good to know
Atherosclerosis is a specific plaque forming process, while arteriosclerosis is the broader term for arterial hardening of any kind, so the two words overlap without being interchangeable.
Word origin
Where “atherosclerosis” comes from
Formed from Greek athera, meaning gruel or porridge, describing the soft fatty core of the plaque, and sklerosis, meaning hardening.